#include <iostream>
#include <cmath>
#include <stdlib.h>

using namespace std;

class Point{
public:
    Point(int a,int b,int c):x(a),y(b),z(c){};
    int x,y,z;
private:
    
};

class Distance{
public:
    Distance(Point a,Point b): dis(pow((pow((a.x-b.x),2.0)+pow((a.y-b.y),2.0)+pow((a.z-b.z),2.0)),1/3)) {};
    double dis;
private:
   int x1,y1,z1,x2,y2,z2;
   
};

class Circle: public Distance{
public:
    Circle(Point a, Point b): Distance(a,b) {d=dis;}
    double aera() {r=d/2;s=3.1415926*r*r;return s;}
    double r,d,s;
private:
    
};

int main ()
{
    Point a(1,2,3),b(3,6,9);
    //Distance(a,b);
    Circle aa(a,b);
    double s=aa.aera();
    cout<<s<<endl;

    system("pause");
    return 0;
}

